Check that conv and conv->conv are non-null (fixes cron segfault)

debian/changelog

@@ -1,3 +1,9 @@
+libpam-csc (1.4) stable testing; urgency=low
+
+  * Check that conv and conv->conv are non-null (fixes cron segfault)
+
+ -- David Bartley <dtbartle@csclub.uwaterloo.ca>  Sun, 14 Oct 2007 01:59:54 -0400
+
 libpam-csc (1.3) stable testing; urgency=low
 
   * Added allowed usernames check

pam_csc.c

@@ -144,6 +144,8 @@ int pam_csc_print_message(pam_handle_t* pamh, char* msg, int style)
 
     /* output message */
     WARN_PAM( pam_get_item(pamh, PAM_CONV, (const void**)&conv) )
+    if(!conv || !conv->conv)
+        goto cleanup;
     messages[0] = &message;
     message.msg_style = style;
     message.msg = msg;